An examination of three aspects of procedural memory in Alzheimer's disease and in normal aging
This study examines the effect of Alzheimer's Disease (AD) on three aspects of procedural memory, verbal, visual, and motor. Participants (N = 36) were assigned to one of three groups, Normal Control (N = 12, age 68 to 80 years), Mild Alzheimer's (N = 12, age 74 to 91 years), and Moderate Alzheimer's (N = 12, age 70 to 87 years) according to their performance on the Mini-Mental State Examination (MMSE). The following scores differentiated the groups: (1) Normal Control = 27 to 30 points, (2) Mild AD = 22 to 26, and Moderate AD = 17 to 21 points. A Word-Stem Completion Test (WSCT) assessed verbal memory; the Gollin Incomplete Pictures Test (GIPT) measured visual memory; and a Pursuit Rotor Test (PRT) was used for motor memory. Contrary to previous research, no significant differences among the groups were found on the WSCT. There was a significant difference between the control group and the Moderate AD group on performance on the PRT. It was also found that there was no significant learning across trials for any of the groups. Neither of the findings on the PRT is supported by previous research. The performance of the Moderate group was significantly impaired when compared to the Normal Control group on the GIPT, a finding consistent with previous studies. It was also found that there was a significant correlation between the GIPT and the PRT.